Realization of Lange Coupler using Hybrid Technology and its Characterization

Abstract

Lange Coupler implementation combining Thin and Thick Film technologies is presented in this article. The standard Lange Coupler on 0.635 mm thick alumina is realized and taken as reference module. The via concept implemented for the direct mounting on assembly board and the continuity though via is ensured using thick film conductor paste. This approach is useful in dense RF boards as it provides ease of mounting with no leads like Quad-Flat-No-lead (QFN). Additionally, unmetallized alumina nitride substrate is taken and Lange Coupler structure is realized with photolithography technique. The characterization of all the three structures are carried out. The implementation methodology utilizing thick film gold paste and wet etching provides greater flexibility on substrate selection and tight tolerances in achieving fine feature sizes without compromising circuit performance. The design implementation methodology, characterization and associated aspects are detailed in this article.